Dynamic tensile properties of mild steel sheets after strain aging

Abstract
The dynamic behavior of ultra low carbon mild steels was experimentally examined in order to know the contribution of the pure ferrite phase on the strain rate sensitivities. The influence of solute carbon atoms, in Non-IF steel, on the dynamic work-hardening behavior was studied by comparing it with IF steel without solute carbon atoms, this to clarify the aging effects of the solute carbon atoms. Dynamic tensile test has been performed before and after strain aging. The relation between dynamic and static flow stresses at various strains is almost identical regardless of solute carbons and strain aging. The strain aging seems to augment internal stress, and seems to have no effect on the effective stress. The static deformation forms the dislocation cell structure but the dynamic deformation does not. In the case that the solute carbon exists and strain aging occurs, the weak cell structure is observed after dynamic deformation. It seems to consist of the immobile dislocations which are pinned with carbon atoms by strain aging.